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The Olive-sided Flycatcher is a deep olive-grey with a white breast and belly. The dark patches on either side of its white belly look like an unbuttoned vest. Its bill is short and stout, the top bill is dark and the bottom one is light with a black tip.

Weight: 29 to 35 g (1.0 to 1.2 oz). Length: 18 to 20 cm (7 to 9 in).

Report Olive-sided Flycatcher sightings to 

The Olive-sided Flycatcher arrives in the Northwest Territories in late May and early June. Females incubate three to four eggs for about 15 days. The Olive-sided Flycatcher leaves the Northwest Territories in late July to early August and winters in South and Central America.

The Olive-sided Flycatcher eats flying insects. It perches on tall trees or snags and waits for insects to fly by before pursuing its prey. Typical habitat is wetlands, mature conifer forests, and areas with young trees including those created by forest fires or clear-cuts. The Olive-sided Flycatcher also uses open forests containing tall trees or snags for perching.

The Olive-sided Flycatcher has a loud song that sounds like "quick, THREE BEERS". Females will also sing when agitated or when close to their nest.

Like many other species of birds that feed on flying insects, the Olive-sided Flycatcher experienced a decline of about 70% since the 1970s. The reasons for the decline are not well understood but could be related to the impacts of multiple threats or cumulative effects affecting Olive-sided Flycatchers on their breeding grounds, wintering grounds, and during migration. A 10% increase was recently estimated in Canada over a ten year period (2009-2019). 


Potential threats to Olive-sided Flycatcher in the Northwest Territories include habitat loss and degradation from human activities; large-scale decline or some other change in insect populations; and human activities resulting in increased numbers of predators and declining food sources. 

Household cats kill over two billion birds a year in North America. You can help birds by keeping your cats inside.

COSEWIC assessed Olive-sided Flycatcher as Threatened in 2007 and Olive-sided Flycatcher was listed as Threatened under the federal Species at Risk Act (SARA) in 2010. In 2018, COSEWIC re-assessed Olive-sided Flycatcher as Special Concern because the rate of population decline has slowed over the past decade, although concerns remain about threats and the long-term decline. The SARA listed status was changed to Special Concern in 2023.

Olive-sided Flycatchers and their nests are protected under the federal Migratory Birds Convention Act.  A national recovery strategy for Olive-sided Flycatcher is available on the federal Species at Risk Public Registry.

Dehcho Gwich'in North Slave / Tłı̨chǫ Sahtú South Slave